Thomas Aquinas believed that there was an appropriated assimilation or likeness to God found in creatures and creation. Some likeness must be found between an effect and its cause. It is in the nature of any agent to do something like itself. Thus, God also gives to creatures and creation all their perfections; and thereby he has with all creatures a likeness.
Additionally, the cause of variety and the multitude of things in creation find their cause in God. Thomas contrasts himself with early Greek philosophers such as Democritus and the other atomists who argued that the distinction of things come from chance according to the movement of matter. Thomas follows Anaxagoras in attributing the multitude to matter and to the agent involved. Thomas identifies this agency as God since he is the creator of matter and thus the efficient cause behind the existence of the matter. Additionally, the universality of things and the perfection of the universe must precede forth from the intention of the first agent—God. Thomas states that the distinction and variety reflects the divine goodness.
For he brought things into being in order that his goodness might be communicated to creatures, and be represented by them; and because his goodness could not be adequately represented by one creature alone, he produced many and diverse creatures, that what was wanting to one in the representation of the divine goodness might be supplied by another. For goodness, which in God is simple and uniform, in creatures is manifold and divided and hence the whole universe together participates the divine goodness more perfectly, and represents it better than any single creature whatever.